For data transmission networks using circuit-switching, such a method is set down in the ITU-T standard (International Telecommunication Union—Telecommunication Standardization Sector)—Q.951.7, “Stage 3 description for number identification supplementary services using DSS 1: Malicious Call Identification (MCID)”. The performance feature is used in particular in conjunction with the preparation of legal proceedings.
In a data transmission network using circuit-switching the data is transmitted in time channels in accordance with a time-division multiplex method. Before data transmission takes place, the time channels are through-connected in a connection establishment phase and then remain reserved for the terminal devices involved in the call for the duration of the call. The data comprises for example call data or video data, such as is produced during a videoconferencing session.
With regard to the known method, the identifier is a subscriber number whose format is set down in the ITU-T standard E.164. The subscriber number is the means by which the calling terminal device, in other words the terminal device which transmits the call, can be reached in the circuit-switched data transmission network.
With regard to the known method, the signaling units are switching centers in a public telephone network. The signaling units perform signaling in accordance with a standardized protocol, in particular as per ISUP (Integrated Services digital network—User Part). With regard to the known method, both terminal devices are always situated in the circuit-switched data transmission network.